Normal failure on the SAP hard plastic line.

Many people replace the entire section with rubber hose, but keep in mind it may not last more than 7-8 years due to the heat from the exhaust.

 

I have an issue with my 2001 330Ci, I have p0491 and p0492 pop up once the SAP stops pumping after a cold start. I removed and replaced the long plastic pipe that runs along side the passenger side of the motor, replaced the rubber hoses connected to the pipe that connects to each end. I still get this code. I removed hose from the value (round metal valve) and blew into the hose that runs to the back of the manifold, air blows freely, is it not suppose to do that or be airtight?

 

Yes, if you blow into the small hose that connects to the Kombi valve at the front of the engine with the large SAP hose connected, it will blow air freely. This is due to the what the electrical control valve under the rear of the intake operates.

Assuming this is your 300k mile machine, if it has original O2 sensors, it is likely far overdue for replacement. In theory you should be installing you 3rd set of replacement O2 sensors in this car.

But assuming you have OBDFusion, you can Log the PID's and we can see exactly how well the O2 sensors are functioning on cold start.

 

Interesting, so your theory is that the SAP is fine? I keep getting the p0491 and p0492 error at cold start. I have a generic OBD2 reader and after monitoring the readiness monitor, the OH (Oxygen Heater) passed, but when it got to secondary air pump, it didn't pass. I guess I have to get OBD Fusion. I am on all original O2 sensors on the car. do I need to buy a Bluetooth adapter to plug in to the OBD2 port?

 

I kind of guessed you may have the original O2 sensors at 300k+ miles.

As I said, you should be at the point of installing the 3rd set of O2 sensors on this car! I would not worry too much about Post-cat sensors, they are not really used for SAP monitoring and are a real PITA to replace as compared to the Pre-cat O2 sensors. You may still have a problem with the vacuum hoses to or some other part of the SAP system, however, the Pre-cat O2 sensors are CRITICAL to inform the DME that the SAP system is working.

See this thread - http://forum.e46fanatics.com/showthread.php?t=1041726

If you have a smart phone or table, get an OBDII App and interface so you can read the codes along with Live/Realtime or Freeze Frame data then you will know exactly what is going on with the engine fuel management system.

OBDFusion for Android is is $3.99.

Android Bluetooth adapter - http://www.amazon.com/dp/B00WPW6BAE/...BWNPO9BZ&psc=1

OBDFusion, for the iProducts it is $9.99.

For iProducts you NEED a Wifi adapter or a very specialized LE Bluetooth adapter.

iProducts WiFi adapter - http://www.amazon.com/dp/B00WPW6BAE/...BWNPO9BZ&psc=1

The adapter links I posted were some of the cheapest and smallest interfaces at the time, you should search and see if there are others that may be slightly cheaper. You can also get similar interfaces on ebay, but BE VERY CAREFUL where the seller is located. You can wait WEEKS for an interface from Asia either via Amazon or ebay. You can a US seller that has inventory in the US. I ALWAYS make sure any Amazon items CLEARLY state "Fulfilled By Amazon" before I pull the trigger.

Or for iOS and Bluetooth see special note below.

This info is new/hot off the press, OBDFusion WILL be supporting Bluetooth on iOS.

BUT, PLEASE NOTE. For iOS to support BT it apparently has to be some Low Energy version of Bluetooth. There are only a few of the Low Energy BT interfaces on the market at the moment, or at least that OBDFusion developers have fully tested.

The LELink Bluetooth LE adapter.

Check on Amazon for LELink info and pricing.

The Carista Bluetooth LE adapter.

http://www.caristaapp.com/hardware/

So for the basic OBFusion, you are at $30 or less for iProducts using a Wifi interface or slightly more if you choose a Bluetooth LE interface and under $20 for Android. Very worth while once you find out what you can do with these Apps.

If you want to step up to a faster and higher quality interface, check out the OBDLink interfaces, there are 3 versions of the interface. Note the OBDLink interfaces come with an OE version of OBDFusion so think about that before you decide to buy OBDFusion, it may save you between $4 and $10 on a duplicate App.

http://www.obdlink.com/

As for OBDFusion set up, read this thread. Note that OBDFusion used to be called Touch Scan so this info is all relevant, but there may have been some minor software changes to the App.

http://forum.e46fanatics.com/showthread.php?t=1080334

Also you need to set up a DropBox Free account and learn how to upload the .CSV files to

The easiest way it to set up a DropBox Free account is on your computer.

BUT, WARNING - YOU DO NOT WANT TO INSTALL THE DROPBOX SOFTWARE. IT WILL DO SOME CRAZY THINGS IF YOU DO NOT DISABLE AND MANAGE IT.

What you do is during the DropBox Free sign up process, once you enter your user name and password, when the prompt shows up to download and install the software, just use the Back browser button. This will take you to your Account and then you can upload the files either directly from the phone once you enter the DropBox user name and password in the OBDFusion App.

Then when you find the files in DropBox, choose Share, then a URL will pop up, just copy and paste the URL back into a forum reply here.

 

I am still thinking it will be a leak in a vaccuum hose; doesn't seem likely to get p0491 and p0492 at the same time if its a faulty O2 sensor. I need to check the hoses near the back of the intake manifold. I did change out the salmon relay because after I left the engine cool down overnight, the SAP never came back on, I wasn't getting any power from the cable that plugs into the SAP using a multimeter. Now its back on and works fine, just need to go after those old hoses. BTW: My O2 sensors should go in the record books for being original OEM after almost 15 years of use.

 

Check the vacuum hose, however, if you read this thread you would understand how bad/Lazy O2 sensors could cause both P0491/P0492 - http://forum.e46fanatics.com/showthread.php?t=1041726

With OBDFusion and the interface you could see exactly how the O2 sensors are behaving when cold. They may be fine, they may be shot.

 

:bump:

I've been trying to track down my P0491/P0492 codes for a few weeks now. Would really like to get it resolved so the car can pass emissions and I can get a permanent tag.

- 136K, no service records.
- Car runs perfectly under all circumstances.
- Replaced all rubber vacuum lines associated with the SAP system, including the blind plug on the manifold.
- Air pump works.
- The round SAP valve seems to work since when I disconnect it from the air pump, no exhaust comes out.

What's my next move? Get OBDFusion for my iPod (assuming I can) and check the O2 sensor operation?

 

Yes

But here is the thing, the MAJORITY of E46's on the road probably have the original O2 sensors still installed. O2 sensors are consumable sensors, they are suggested to be replaced at 100k miles. Some last much longer, some fail or get lazy earlier.

If Pre-cat O2 sensors appear to be original, I would just replace them regardless.

You can wait on the interface for OBDFusion and then Log the sensor behavior and learn at the end of the day they should probably be replaced, or you can proactively replace them, and get the OBDFusion interface. You can also "Reset" the codes, even if there are no current codes and see if the SAP Readiness Monitor will clear, it should clear on the very first cold start after sitting overnight if everything is working properly. Just start the engine and allow it to idle for 2 minutes before driving the car.


You should be able to buy standard, non Wideband O2 sensors for about $45 each if you shop them and find coupons. You want Bosch Direct Fit Sensors.

Suggest you use this Bosch site to find the CORRECT part numbers - https://www.boschautoparts.com/en/

Check the following:

Amazon
RockAuto
Advance
AutoZone
PepBoys
O'reilly's

Look for online coupons for Advance and AutoZone, they often have good deals for online orders that you can even pick up in the store.

The SAP system is actually pretty easy to sort out.

http://forum.e46fanatics.com/showthread.php?t=1097432

 

Thanks very much! Very helpful indeed.

I have a small orange Actron OBD2 scan tool that I've used to clear the codes each time I work on the system. Each time the SES light stays off the first cold start, but comes on after the air pump shuts off during the second cold start. Any clues as to what that means?

 

The Pre-cat O2 sensors are what determines if the SAP is operating and if it is operating properly. These are KEY in providing info to the DME as to how the SAP system is performing.

The problem is EITHER the Pre-cat O2 sensors are lazy, if original, highly likely the culprit, AND/OR there is a problem between the SAP pump and the Kombi and/or the control circuits and vacuum lines that operate the valve on the front of the cylinder head.

Read this thread and look at the graphs in post #22 & #25 carefully, pretty self explanatory I would think.

 

You are a gentleman and a scholar. Much appreciated.

I downloaded OBDFusion for my iPod. Now just need to get an adapter for the OBD port.

One question: If the pre-cat O2 sensors are "lazy," wouldn't that affect how the car runs in closed loop? Like I said, the car runs flawlessly. Is monitoring the SAP really the only thing those sensors have to do?

 

The Pre-cat O2 sensors have everything to do with the SAP monitoring and the overall engine fuel system management.

When the O2 sensor get lazy they are slow to react when warming up and they can do a reasonable job feeding info back to the DME once fully warmed up. Degraded O2 sensors may impact fuel economy and performance, but not usually to the point that the driver would really notice.

The first cold start Log will clearly show if the Pre-cat O2 sensors are lazy and likely the reason the SAP Monitor is not clearing.

 

Replaced my pre-cat O2 sensors last night with Bosch direct-fit replacements (#13477) from RockAuto. $47 apiece. Very easy job.

Cleared the codes last night, drove the E46 to work this morning. So far so good! Will let you know if I'm able to pass emissions and get a plate (finally!).

Really appreciate the advice. :thumbsup:

 

Evap Monitor will be the most difficult Monitor to Clear/Ready/Pass.

Keep the fuel tank around 3/4 full and keep driving normally.

Many states all 1-2 Readiness Monitors to not be in the Clear/Ready/Pass state for older vehicles and still allow and possibly pass inspection.

 

I'm happy to report the car PASSED emissions with flying colors. :woot:

jfoj, you are a steely-eyed missile man. Next time you're in Chattanooga let me buy you a beer or your beverage of choice. :dave:

 

Spannerhead,

Glad you were successful with getting the car to finally pass inspection. It can be really frustrating when you are up against the wall and there are no specific clues as to what to do in order to resolve Readiness Monitors that will not turn to Ready/Pass/Clear. Fresh and healthy O2 sensors are key for most all of the Readiness Monitors to turn to Ready/Pass/Clear. Lazy sensors will cause the Monitors to drag on and become delayed to the point that the Emission Monitoring process may come to a crawl.

I think overall the majority of the E46's on the road have the original Pre-cat O2 sensors still installed and at the end of the day when it doubt they should be replaced to provide optimal performance, fuel economy and emission reliability.

Once the Pre-cat O2 sensors are replaced they are most likely good for the next 100k miles assuming a heater circuit in a sensor does not fail.

 

Good info. BTW, I still intend to buy the OBD2 adapter for my iPod. Don't think I don't want to "learn to fish."

 

Hello all,

Appreciate all the help offered here as it kept me going during my travails dealing with P0492/P0492. Finally got the codes extinguished after following the troubleshooting instructions but noticed (I think) something

I hadn't seen mentioned on any of the websites I went to for info....I think the SAIP relay schematic in the Bentley Manual shows the wrong SAIP relay K6304 pin configuration which I discovered when I found

that the relay could be put in it's socket in two ways..pin 30 is actually pin 87 and vice versa in the schematic on ele-85 and probably elsewhere but I didn't check. I found that with the relay accidently installed

upside down and the rest of the system working fine, Codes P0491 and P0492 were replaces with P0414. Once the relay was installed properly, all codes went away and haven't returned after several driving cycles.

V/R, El Ced